The unstoppable Juggernaut is one of the X-Men's fiercest villains and a fan-favorite to many Marvel Comics aficionados. He has the ability to take on multiple foes at once and still continue to his objective; he's not called "unstoppable" for nothing. He's not without his weaknesses, but a moment in Exiles #4 grants Juggernaut the ability to remove one of his said weaknesses, turning him into a truly unstoppable force.
The Juggernaut began life as Professor Charles Xavier's step brother, and immediately took a dislike to the future X-Men leader. Cain Marko was a bully at heart, who resented Xavier for his intelligence and success. However, for all his bravado and physical strength, Marko's cowardice overcame him during the Korean War, and deserted while under fire. Chased by Xavier (who also served and was able to walk at the time), the two stumbled upon a cave in which Marko found the Ruby of Cyttorak. Ignoring Xavier's warnings, Marko grabbed the ruby, causing the cave to collapse but transforming Marko into a human Juggernaut.
Juggernaut would eventually emerge from the collapse to attack Xavier's mansion directly in his debut issue, and would continue to be a villainous thorn in the X-Men's side for decades to come. In Exiles #4, the Juggernaut returns to wreak havoc again. The eponymous team is traveling through space and time and finds themselves onboard Blackbeard's pirate ship (the Thing in reality). Blackbeard and his crew face Admiral Henry Gyrich, who commands "...a ship that cannot be burned. A ship that cannot be blasted. A ship that cannot be sunk!" At this cue, the Juggernautical appears: a Juggernaut in the form of a boat.
The Juggernautical's appearance is, for lack of a better word, silly; Marko has apparently replaced his metallic armor with wooden planks, yet they fend off an entire ship's worth of heroes. But while the classic Juggernaut could be defeated by removing him from the ground, this one floats on water, easily negating Marko's most famous weakness. Thankfully, the Juggernautical is also controlled by a magic book, which the heroes on Grimm's ship were able to retrieve and toss the device in the water, neutralizing the threat.
The Juggernautical has only made one appearance in Marvel canon thus far. It's clear that the company is creating new and interesting variants when it comes to their classic characters. The Juggernaut still remains unstoppable in popularity if not necessarily in combat.